1. Field of the Invention
The present invention relates to an uninterruptible power supply, an uninterruptible power supply system and a shutdown processing program product.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2005-92859 (FIGS. 1 to 3, FIG. 5, the column of Mode for Carrying out the Invention, paragraphs 0054, 0055, 0065 and the like) discloses a redundant system. In this redundant system, a plurality of power supplies are connected to an information processor with communication lines of a serial communication method in compliance with the RS-232C standards, and the USB (Universal Serial Bus) standards. A UPS monitoring part and a UPS communication part of the information v processor monitor the states of a plurality of power supplies and control them.
As in the Patent Document, power feed at the time of a power failure can be made redundant by connecting a plurality of uninterruptible power supplies to the information processor. However, in such a configuration as that of the redundant system of the Patent Document, the information processor monitors and controls the uninterruptible power supplies, and therefore, a plurality of uninterruptible power supplies need to be individually connected to the information processor with exclusive communication lines of a serial communication method.
In contrast to this, it is conceivable to connect an information processor and uninterruptible power supplies by using networks used in, for example, the Internet, a LAN (Local Area Network) and the like. Thereby, the uninterruptible power supplies do not have to be connected to the information processor by individual exclusive lines.
However, an indefinite number of devices are connectable to a network. The network cannot be occupied by the respective uninterruptible power supplies. Therefore, when the uninterruptible power supplies send power failure detection notification or the like to the load device, to the network, the notification is not always provided to the load device in the timing when the uninterruptible power supplies detect the power failure. When the other devices use the network, the power failure detection notification to the load device is provided to the load device late, for example.
If the power failure detection notification or the like is provided late like this, power feed to the load device from the uninterruptible power supplies is likely to stop before completion of a predetermined shutdown sequence even if the load device starts the predetermined shutdown sequence based on the notification. The load device sometimes cannot finish shutdown processing normally.
Especially when a plurality of uninterruptible power supplies are connected to one network, if a power failure occurs, a plurality of the uninterruptible power supplies are to transmit power failure detection notification to the network substantially at the same time. Accordingly, the possibility of the power failure detection notification of any of them is provided to the load device late is not low.
Further, in the network, network devices such as a hub device and a router device are used. The network devices operate by power feed. When a power failure occurs and an uninterruptible power supply performs a backup power feed operation, power feed to the network devices is likely to stop. When power feed to the network devices stops, communication through the network cannot be performed. When the network devices stop, a start instruction of shutdown or the like which is to be transmitted to the load device by the uninterruptible power supply is not transmitted to the load device. The load device which starts shutdown based on the start instruction of shutdown cannot start shutdown processing.
The present invention has an object to obtain an uninterruptible power supply, an uninterruptible power system and a shutdown processing program product with which the uninterruptible power supply and its load device are connected by a network, and the load device which is supplied with power by the uninterruptible power device can properly execute shutdown processing.